KR20180101127A - Spatial lattice modulation method in wireless communication system supporting multiple input multiple output and apparatus using thereof - Google Patents

Abstract

The present invention relates to a spatial grid modulation method in a wireless communication system for supporting a multiple input multiple output (MIMO) scheme and a device using the same. A transmitter device in a wireless communication system for supporting a MIMO scheme includes: multiple transmission antennas; and a processor which maps input data onto combinations of multiple virtual antenna dimensions and one or more modulation symbols, hereinafter referred to as a dimension-symbol combination. The processor also generates one or more modulation symbols based on the mapping and transmits the modulation symbols through one or more of the transmission antennas. The virtual antenna dimensions can be defined with antennas transmitting equivalent real signals in complex signals being transmitted by the transmission antennas.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial grid modulation method and a device using the spatial grid modulation method in a wireless communication system supporting multiple input multiple output

Embodiments of the present invention relate to a spatial modulation method for constructing a lattice in an antenna space and a signal space in a wireless communication system supporting multiple input multiple output (MIMO) and an apparatus using the same.

A multiple input multiple output (MIMO) system can achieve improved spectral efficiency and higher reliability than a single input single output (SISO) system. In the MIMO system, individual modulated symbols are transmitted from the respective antennas of the transmitter, so that spatial multiplexing can be achieved. However, complicated signal processing is required for the receiving end to process inter-channel interference (ICI). To solve this problem, a linear decoding algorithm such as V-BLAST (Vertical-Bell Labs Layered Space-Time Architecture) has been developed. However, as the interference increases, the performance of the system deteriorates.

Recently, spatial modulation (SM) technology has been developed to solve the inter-channel interference problem. The spatial modulation technique does not use all of the plurality of transmit antennas included in the transmitter during transmission but uses only one transmit antenna. This can eliminate interchannel interference at the receiving end and obtain additional information from the index of the deactivated or active antenna.

Generally, the spatial modulation technique divides the data to be transmitted into two bit blocks and transmits them. The first bit block contains additional information from the index of the single active antenna used for transmission among the transmitters' antennas. The second bit block includes symbols of signals transmitted by each antenna. Therefore, the demodulation complexity in the transceiver is reduced and the frequency efficiency similar to that of the MIMO system can be obtained. In addition, the spatial modulation technique can be combined with Orthogonal Frequency Division Multiplexing (OFDM) technology and used for wideband communication.

Recently, a generalized spatial modulation (GSM) method, a multiple active spatial modulation (MA-SM) method, a quadrature spatial modulation (QSM) -SM: Joint Mapping Spatial Modulation) method have been proposed. However, a spatial modulation method that generalizes these spatial modulation methods has not yet been proposed, and a method of multiplexing in spatial modulation has not yet been developed.

SUMMARY OF THE INVENTION The present invention provides a spatial lattice modulation method and apparatus that considers all combinations of antenna space and signal space in a wireless communication system supporting multiple input multiple output.

Another aspect of the present invention is to provide a method and apparatus for reducing a bit error rate in a wireless communication system supporting multiple input multiple output.

Another aspect of the present invention is to provide a method and apparatus for multiplexing spatial modulation methods in a wireless communication system supporting multiple input multiple output.

A further object of the present invention is to provide a method and apparatus for reducing the complexity of receiving signal decoding in a wireless communication system supporting multiple input multiple output.

According to an aspect of the present invention, a transmitter in a wireless communication system supporting Multiple Input Multiple Output (MIMO) includes a plurality of transmit antennas and a plurality of virtual antenna dimensions and at least one modulation (Hereinafter referred to as a dimension-symbol combination), generating at least one modulation symbol based on the mapping, and transmitting the at least one modulation symbol through at least one of the plurality of transmit antennas, And the virtual antenna dimension may be defined as an antenna that transmits an equivalent real signal among the complex signals transmitted by the transmission antenna.

If different, the processor may map the bits of the data to the dimension-symbol combination based on the mapping information preset in the transmitting apparatus.

According to another aspect, the mapping information may be generated based on the number of virtual antenna dimensions and the number of symbols used for modulating the data.

According to another aspect of the present invention, the processor maps the generated at least one modulation symbol to a predetermined symbol, and transmits an antenna for transmitting a modulation symbol mapped to the predetermined symbol among the plurality of antennas based on the mapping information You can choose.

According to another aspect of the present invention, when the number of the at least one modulation symbol is equal to the number of the preset symbols, the processor maps the generated at least one modulation symbol to the predetermined symbol one-to-one, When the number of the at least one modulation symbol is smaller than the number of the preset symbols, select some of the predetermined symbols and map the generated at least one modulation symbol to the selected symbol.

According to another aspect of the present invention, the predetermined symbol may be a symbol selected in order of low powers among symbols corresponding to a predetermined grid generation matrix.

According to another aspect, the processor groups the plurality of transmit antennas into a first transmit antenna group and a second transmit antenna group, and groups the first bit string of the data into a dimension-symbol combination And map a second bit stream of the data to a dimension-symbol combination for the second transmit antenna group.

According to another aspect of the present invention, in a wireless communication system supporting multiple input multiple output, a transmitting method of a transmitting apparatus includes inputting a plurality of virtual antenna dimensions and a combination of at least one modulation symbol (hereinafter referred to as a dimension-symbol combination) ), Generating at least one modulation symbol based on the mapping, and transmitting the at least one modulation symbol via at least one of the plurality of transmit antennas, wherein the virtual antenna dimension And may be defined as an antenna for transmitting an equivalent real number signal among the complex number signals transmitted by the transmission antenna.

According to another aspect of the present invention, a receiving apparatus in a wireless communication system supporting multiple-input multiple output includes at least one receiving antenna for receiving signals from a transmitting apparatus including a plurality of transmitting antennas, And a processor for decoding the signal based on mapping information defined on the basis of the number of virtual antenna dimensions and the number of symbols to be used, and the virtual antenna transmits a real number signal among the complex number signals transmitted by the transmission apparatus Antenna. ≪ / RTI >

According to another aspect of the present invention, there is provided a receiving method of a receiving apparatus in a wireless communication system supporting multiple input multiple output, comprising: receiving a signal from a transmitting apparatus including a plurality of transmitting antennas using at least one receiving antenna; And decoding the signal based on mapping information defined based on the number of virtual antenna dimensions and the number of symbols used for modulating the signal, wherein the virtual antenna comprises a complex number signal May be defined as an antenna for transmitting a real signal.

According to the present invention, enhanced frequency efficiency can be achieved in a wireless communication system supporting multiple input multiple output by using a spatial lattice modulation method of generating a cubic lattice structure in a spatial dimension.

Also, according to the present invention, the bit error rate can be reduced by mapping the transmission symbol vector of the cubic lattice structure to the transmission symbol vector of the non-cubic lattice structure.

Also, according to the present invention, the complexity of transmission and reception can be reduced by using the multiplexing / demodulation method by grouping the antennas of spatial lattice modulation.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.
2 is a block diagram illustrating a transmitting apparatus according to an embodiment of the present invention.
3 is a graph illustrating frequency efficiency of a spatial lattice modulation method and an existing spatial modulation method according to an embodiment of the present invention.
4 is a graph illustrating a bit error rate of a spatial lattice modulation method and an existing spatial modulation method according to an embodiment of the present invention.
5 is a block diagram illustrating a transmitting apparatus according to another embodiment of the present invention.
6 is a flowchart showing a transmission method according to the first embodiment of the present invention.
7 is a flowchart showing a transmission method according to a second embodiment of the present invention.
8 is a flowchart showing a transmission method according to the third embodiment of the present invention.
9 is a block diagram illustrating a receiving apparatus according to an embodiment of the present invention.
10 is a flowchart illustrating a receiving method according to an embodiment of the present invention.
11 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 may be a wideband cellular communication system. The wireless communication system 10 includes at least one base station 11 (evolved-NodeB, eNB). Each base station 11 provides communication services to specific cells (15a, 15b, 15c). A cell may be divided into a plurality of regions (referred to as sectors).

A user equipment (UE) 12 may be fixed or mobile and may be a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The base station 11 may be referred to by other terms such as a base station (BS), a base transceiver system (BTS), an access point, a femto base station, a home node B, and a relay. Cells are meant to cover various coverage areas such as megacell, macrocell, microcell, picocell, and femtocell.

Downlink (DL) refers to communication from the base station 11 to the terminal 12, and uplink (UL) refers to communication from the terminal 12 to the base station 11. In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. For uplink and downlink transmission, a time division duplex (TDD) method and a frequency division duplex (FDD) method using different frequencies may be used.

There is no limitation on the multiple access scheme applied to the wireless communication system 10 according to the present invention. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier- , OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA may be used. Multiple access schemes for downlink and uplink transmissions may be different. For example, OFDM (Orthogonal Frequency Division Multiplexing) may be used for the downlink, and Single Carrier-Frequency Division Multiple Access (SC-FDMA) may be used for the uplink.

The SC-FDMA scheme conforms to the basic principle of the OFDM scheme and is a modification of the OFDM scheme in consideration of the PAPR (peak to average power ratio) aspect. Therefore, although the case where the multiple access scheme of the wireless communication system 10 according to the present invention is OFDM is explained as a main example, the embodiments and features according to the present invention are equally applicable to SC-FDMA and other multiple access schemes . That is, the additional embodiments that are applied to other multiple access schemes having the same or similar features as those of the embodiments of the present invention are also all embodiments of the present invention.

In the OFDM or SC-FDMA scheme, the transmitter and the receiver perform communication using a plurality of orthogonal subcarriers. The signal (or data symbol) of the transmitter is modulated by the OFDM scheme and transmitted to the receiver, which is also referred to as an OFDM symbol or an SC-FDMA symbol. An IDFT (Inverse Discrete Fourier Transform) and a DFT (Discrete Fourier Transform) can be used to implement communication according to the OFDM scheme. That is, the transmitter may take an IDFT on the data symbols to generate an OFDM symbol and transmit it to the receiver. The receiver can recover the original data symbols by taking a DFT on the received OFDM symbol.

1st Example : A Spatial Grid Modulation Method for Generating a Cubic Grid Structure at Spatial Dimension

2 is a block diagram illustrating a transmitting apparatus according to an embodiment of the present invention.

2, the transmitting apparatus according to the present embodiment includes an encoding unit 210 encoding an input data, an interleaving unit 220 interleaving data input from the encoding unit 210, A modulator 230 for modulating data inputted from the interleaving unit 220 using a spatial modulation method according to an embodiment of the present invention and a plurality of modulators 230 for modulating the data modulated by the modulator 230 Lt; RTI ID = 0.0 > 240 < / RTI > At least one RF chain may be provided between the modulator 230 and the transmission antenna 240. The number of RF chains (N _RF ) may be equal to or less than the number of transmit antennas (N _t ).

Hereinafter, a method by which the modulator 230 performs spatial lattice modulation according to an embodiment of the present invention will be described in detail.

The symbol vector received at the receiving antenna of the receiving apparatus can be expressed as Equation (1).

Where y is the received symbol vector, H is the wireless communication matrix, x is the transmit symbol vector, and v is the noise signal at the receive antenna. In Equation (1), y , H , x , and v are both complex signals, and they can be equally expressed as a real signal by Equation (2).

Here, each vector is divided into an in-phase component and a quadrature component, which is twice as large as a dimension of a real vector of a circle, and the constituent elements have a real number value. Therefore, the components of Equation (2) can be expressed by the following Equations (3) and (4).

Hereinafter, the case where the transmitting apparatus includes two RF chains and two transmission antennas (N _RF = N _t = 2) will be described as an example. A transmitting apparatus in which two transmitting antennas are installed can be expressed by an equivalent transmitting apparatus composed of four virtual antenna dimensions (2N _t ) transmitting only real signals as shown in Equation (3). Hereinafter, a virtual antenna dimension for transmitting a symbol is defined as an active dimension.

개의 활성 차원 패턴이 만들어진다. 선택 가능한 활성 차원 패턴 조합을 나타내는 집합을

라 정의하고, 활성 차원에 해당하는 인덱스는 '1'로, 비활성 차원(심볼이 전송되지 않는 가상의 안테나 차원)에 해당하는 인덱스는 '0'으로 두면, 활성 차원 집합

는 다음의 수학식 5로 표현할 수 있다.If the number of active dimensions is N _u , then the number of active dimensions that can be considered in the presence of four virtual antenna dimensions is N _u ∈ {0,1,2,3,4}. When using N _u active dimensions, for each N _u value

Active dimension patterns are created. A set representing selectable active dimension pattern combinations

And the index corresponding to the active dimension is set to '1' and the index corresponding to the inactive dimension (virtual antenna dimension to which no symbol is transmitted) is set to '0', the active dimension set

Can be expressed by the following equation (5).

이라 정의한다. 차원-심볼 조합의 일 예로, 2개의 송신 안테나와 2개의 RF 체인을 포함하는 송신 장치에서 각 활성 차원에 대해 BPSK를 이용할 경우(N_t=2, N_RF=2, M=2), S ₀ , S ₁ , S ₂ , S ₃ , S ₄ 는 다음의 수학식 6으로 표현이 가능하다. 이 경우, 각 활성 차원에서 전송 가능한 심볼은 '+1', '-1' 이다.The modulation unit 230 performs data modulation by combining the active dimension combination and the symbols to be used in each active dimension. More specifically, the modulator 230 selects an active dimension combination, and one of the symbols used in a predetermined modulation scheme is assigned to each selected active dimension. The predetermined modulation scheme may be, for example, PAM (Phase Amplitude Modulation), QAM (Quadrature Amplitude Modulation), PSK (Phase Shift Keying), BPSK (Binary Phase Shift Keying), or the like. The selection of the active dimension combination and the modulation symbol generation order may be reversed. For convenience of explanation, a combination of the active dimension (antenna dimension used for transmitting a symbol) output from the modulator 230 and modulation symbols is defined as a 'dimension-symbol combination', and the number of active dimensions is N A set of _u dimension-symbol combinations

. As an example of a dimension-symbol combination, when a BPSK is used for each active dimension (N _t = 2, N _RF = 2, M = 2) in a transmitting apparatus including two transmit antennas and two RF chains, S ₀ , S ₁ , S ₂ , S ₃ , and S ₄ can be expressed by the following Equation (6). In this case, the symbols that can be transmitted in each active dimension are '+1' and '-1'.

In Equation (6), each element of the S vector corresponds to four dimensions, an element of '0' corresponds to an inactive dimension, and a element of non-zero value corresponds to an active dimension. The element corresponding to the active dimension represents a symbol such as '+1' or '-1'. The set representing all dimension-symbol combinations is S = S ₁ ∪ S ₂ ∪ S ₃ ∪ S ₄ , and S has a cubic lattice structure in the 4-dimensional spatial dimension. In this specification, a modulation method for generating such a dimension-symbol combination is called a spatial lattice modulation with cubic lattice (SLM-CB). In the above example, the number N _t of transmitting antennas and the number N _RF of RF chains are the same. However, this is also applicable when the number of RF chains N _RF is less than the number of transmitting antennas N _t .

), ((M+1)² - 1)^(N_S) 개의 차원-심볼 조합을 할당할 수 있다. 그러므로 변조부(230)에서 한번에 변조할 수 있는 데이터 비트 수는 다음의 수학식 7과 같다.The above example can be generalized for the cases where N _RF RF chains, N _t transmit antennas, and M symbols for each dimension are used. Up to N _RF antennas among the N _t transmit antennas can be selected and M-PAM (equally, M ^ 2-QAM) symbols can be mapped to the in-phase component and the quadrature phase, respectively, in each selected active dimension. Therefore, when there are N _RF RF chains and N _S transmit symbols are transmitted in the transmit antenna (that is,

), ((M + 1) ² - 1) ^ (N _S ) dimension-symbol combinations. Therefore, the number of data bits that can be modulated at a time by the modulation unit 230 is expressed by Equation (7).

In the case of N _RF = N _t in Equation (7), Equation (7) can be expressed by Equation (8) using binomial theorem.

Therefore, by using the spatial lattice modulation method according to the present invention, since modulation is performed considering all the dimension-symbol combinations used for transmission, maximum frequency efficiency can be achieved for a given number of transmit antennas and symbols to be transmitted have.

3 is a graph illustrating frequency efficiency of a spatial lattice modulation method and an existing spatial modulation method according to an embodiment of the present invention.

3, when two transmit antennas, two RF chains, four receive antennas, and 2-PAM are used for space grating modulation (N _t = N _RF = 2, N _r = 4, M = 2) It can be confirmed that an additional frequency efficiency of about 1.3 bit / sec / Hz is achieved compared with the conventional SM and spatial multiplexing methods.

Referring again to FIG. 2, the modulator 210 may use various assignment rules when modulating (or mapping) the data input of the number of bits corresponding to Equation (7) to one of the dimension-symbol combinations. For example, in the case of using a 2-PAM modulation scheme (N _t = 2, N _RF = 1, M = 2) for each active dimension in a transmission apparatus having two transmission antennas and one RF chain, Based on the same mapping information, four bits can be assigned or mapped to a dimension-symbol combination.

Bit data input Active dimension The transmit symbol vector x _R The transmit symbol vector x 0000 One [+1, 0, 0, 0] [+1, 0] 0001 One [-1, 0, 0, 0] [-1, 0] 0010 2 [0, +1, 0, 0] [0, + 1] 0011 2 [0, -1, 0, 0] [0, -1] 0100 3 [0, 0, +1, 0] [+ 1j, 0] 0101 3 [0, 0, -1, 0] [-1j, 0] 0110 4 [0, 0, 0, +1] [0, + 1j] 0111 4 [0, 0, 0, -1] [0, -1j] 1000 1,3 [+1, 0, +1, 0] [+ 1 + 1j, 0] 1001 1,3 [+1, 0, -1, 0] [+ 1-1j, 0] 1010 1,3 [-1, 0, +1, 0] [-1 + 1j, 0] 1011 1,3 [-1, 0, -1, 0] [-1-1j, 0] 1100 2,4 [0, +1, 0, +1] [0, + 1 + 1j] 1101 2,4 [0, +1, 0, -1] [0, + 1-1j] 1110 2,4 [0, -1, 0, +1] [0, -1 + 1j] 1111 2,4 [0, -1, 0, -1] [0, -1-1j]

Second Example : To reduce the error rate Non-cubic  Spatial lattice modulation method of lattice structure

As a second embodiment, the modulation unit 230 may lower the error rate by mapping the transmission symbol vector generated through the first embodiment to a transmission symbol vector having a lattice structure different from that of the first embodiment. The second embodiment can be used more efficiently than when the transmitting apparatus does not know the channel information.

In the wireless communication system, the transmitting apparatus can reduce the error rate by maximizing the following Equation (9).

The modulator 230 may use a Barnes Wall grid structure to maximize Equation (9). The Barnes Wall lattice structure can maximize Equation 9 when the dimension of the transmit symbol vector x _R is 2 &^lt; ^{n >} (where n is 1, 2, 3, 4). The four-dimensional Branes Wall generation matrix G ₄ can be expressed as Equation (10). Each row in G ₄ represents the basis of the Barnes Wall grid.

Each column of G ₄ is _{g 1 = [2 0 0 0} ] T, g 2 = [1 1 0 0] T, g 3 = [1 0 1 0] T, g 4 = [1 1 1 1] T and can be expressed as a transmission symbol vector x _R it can be generated by the constant linear combination of g ₄ column _{(x R = c 1 g 1} + c 2 g 2 + c 3 g 3 + c 4 g 4, where, c ₁ , c ₂ , c ₃ , c ₄ ∈ Z).

Meanwhile, the modulator 230 may generate a transmission symbol vector using an arbitrary lattice structure (for example, a non-cubic lattice structure) other than the Barnes Wall lattice structure. An algorithm for generating a transmission symbol vector of an arbitrary lattice structure is as follows.

<Algorithm 1> Space Grid Modulation Transmission Symbol Generation Algorithm

, 파워 제약 변수 P , 목표수 K Input : Generation matrix

, Power constraint variable P , target number K

Output : Space Grid Modulation Transmit Symbol Set

. Initialization :

.

를 정의한후, 파워 P를 만족시키는 s 를 검색한다.

. 1. 2N-dimensional column vector _t

And s that satisfies the power P is searched.

.

은

의 대칭그룹 혹은 순열 그룹을 의미한다.

.here,

silver

Quot; refers to a symmetric group or a permutation group of &quot;

.

의 원소가 격자에 포함되는지 확인한다.

2.

Is included in the grid.

이면,

및 P=P+1 를 수행하고, 아니면

로부터

개의 원소를 선택한 후

와 합친다(merge).3. If

If so,

And P = P + 1, or

from

After selecting the number of elements

(Merge).

Then, steps 1 to 3 are repeated.

That is, when generating modulation symbols, the modulator 230 can select a symbol vector only in a column corresponding to a basis of the grid generation matrix G set in advance, but in a sequence having a low power.

The above algorithm is applicable to all integer lattice generation matrices. In the case of the first embodiment, it generates a _4x4 matrix I.

The modulator 230 may select K transmit symbol vectors x _R according to the algorithm. Hereinafter, the set of transmission symbol vectors generated by the modulator 230 according to the second embodiment is defined as S ^BW . Table 2 below shows a case where 81 vectors are selected as an example.

Bit data input Active dimension The transmit symbol vector x _R The transmit symbol vector x 0000000 x [0,0,0,0] ^T [0,0] ^T 0000001 1,2 [1,1,0,0] ^T [1,1] ^T 0000010 1,2 [1, -1,0,0] ^T [1, -1] ^T 0000011 1,2 [-1,1,0,0] ^T [-1,1] ^T 0000100 1,2 [-1, -1,0,0] ^T [-1, -1] ^T 0000101 1,3 [1,0,1,0] ^T [1 + j, 0] ^T 0000110 1,3 [1,0, -1,0] ^T [1-j, 0] ^T 0000111 1,3 [-1,0,1,0] ^T [-1 + j, 0] ^T 0001000 1,3 [-1,0, -1,0] ^T [-1-j, 0] ^T 0001001 1,4 [1,0,0,1] ^T [1, j] ^T 0001010 1,4 [1,0,0, -1] ^T [1, -j] ^T 0001011 1,4 [-1,0,0,1] ^T [-1, j] ^T 0001100 1,4 [-1,0,0, -1] ^T [-1, -j] ^T 0001101 2,3 [0,1,1,0] ^T [j, 1] ^T 0001110 2,3 [0,1, -1,0] ^T [-j, 1] ^T 0001111 2,3 [0, -1,1,0] ^T [j, -1] ^T 0010000 2,3 [0, -1, -1,0] ^T [-j, -1] ^T 0010001 2,4 [0,1,0,1] ^T [0,1 + j] ^T 0010010 2,4 [0,1,0, -1] ^T [0,1-j] ^T 0010011 2,4 [0, -1, 0, 1] ^T [0, -1 + j] ^T 0010100 2,4 [0, -1,0, -1] ^T [0, -1-j] ^T 0010101 3.4 [0,0,1,1] ^T [j, j] ^T 0010110 3,4 [0, 0, 1, -1] ^T [j, -j] ^T 0010111 3,4 [0,0, -1,1] ^T [-j, j] ^T 0011000 3,4 [0, 0, -1, -1] ^T [-j, -j] ^T 0011001 1,2,3,4 [1,1,1,1] ^T [1 + j, 1 + j] ^T 0011010 1,2,3,4 [1,1,1, -1] ^T [1 + j, 1-j] ^T 0011011 1,2,3,4 [1,1, -1,1] ^T [1-j, 1 + j] ^T 0011100 1,2,3,4 [1, -1,1,1] ^T [1 + j, -1 + j] ^T 0011101 1,2,3,4 [-1,1,1,1] ^T [-1 + j, 1 + j] ^T 0011110 1,2,3,4 [1,1, -1, -1] ^T [1-j, 1-j] ^T 0011111 1,2,3,4 [1, -1,1, -1] ^T [1 + j, -1-j] ^T 0100000 1,2,3,4 [1, -1, -1, 1] ^T [1-j, -1 + j] ^T 0100001 1,2,3,4 [-1,1,1, -1] ^T [-1 + j, 1-j] ^T 0100010 1,2,3,4 [-1,1, -1,1] ^T [-1-j, 1 + j] ^T 0100011 1,2,3,4 [-1, -1,1,1] ^T [-1 + j, -1 + j] ^T 0100100 1,2,3,4 [1, -1, -1, -1] ^T [1-j, -1-j] ^T 0100101 1,2,3,4 [-1,1, -1, -1] ^T [-1-j, 1-j] ^T 0100110 1,2,3,4 [-1, -1,1, -1] ^T [-1 + j, -1-j] ^T 0100111 1,2,3,4 [-1, -1, -1,1] ^T [-1-j, -1 + j] ^T 0101000 1,2,3,4 [-1, -1, -1, -1] ^T [-1-j, -1-j] ^T 0101001 One [2,0,0,0] ^T [2,0] ^T 0101010 One [-2,0,0,0] ^T [-2,0] ^T 0101011 2 [0, 2, 0, 0] ^T [0,2] ^T 0101100 2 [0, -2,0,0] ^T [0, -2] ^T 0101101 3 [0,0,2,0] ^T [2j, 0] ^T 0101110 3 [0,0, -2,0] ^T [-2j, 0] ^T 0101111 4 [0,0,0,2] ^T [0, 2j] ^T 0110000 4 [0,0,0, -2] ^T [0, -2j] ^T 0110001 1,2,3 [2,1,1,0] ^T [2 + j, 1] ^T 0110010 1,2,3 [-2,1,1,0] ^T [-2 + j, 1] ^T 0110011 1,2,4 [2,1,0,1] ^T [2,1 + j] ^T 0110100 1,2,4 [-2,1,0,1] ^T [-2,1 + j] ^T 0110101 1,3,4 [2,0,1,1] ^T [2 + j, j] ^T 0110110 1,3,4 [-2,0,1,1] ^T [-2 + j, j] ^T 0110111 1,2,3 [1,2,1,0] ^T [1 + j, 2] ^T 0111000 1,2,3 [1, -2,1,0] ^T [1 + j, -2] ^T 0111001 1,2,4 [1,2,0,1] ^T [1,2 + j] ^T 0111010 1,2,4 [1, -2,0,1] ^T [1, -2 + j] ^T 0111011 2,3,4 [0, 2, 1, 1] ^T [j, 2 + j] ^T 0111100 2,3,4 [0, -2,1,1] ^T [j, -2 + j] ^T 0111101 1,2,3 [1,1,2,0] ^T [1 + 2j, 1] ^T 0111110 1,2,3 [1,1, -2,0] ^T [1-2j, 1] ^T 0111111 1,3,4 [1,0,2,1] ^T [1 + 2j, j] ^T 1000000 1,3,4 [1,0, -2,1] ^T [1-2j, j] ^T 1000001 2,3,4 [0,1,2,1] ^T [2j, 1 + j] ^T 1000010 2,3,4 [0,1, -2,1] ^T [-2j, 1 + j] ^T 1000011 1,2,4 [1,1,0,2] ^T [1,1 + 2j] ^T 1000100 1,2,4 [1,1,0, -2] ^T [1,1-2j] ^T 1000101 1,3,4 [1,0,1,2] ^T [1 + j, 2j] ^T 1000110 1,3,4 [1,0,1, -2] ^T [1 + j, -2j] ^T 1000111 2,3,4 [1,0,1, -2] ^T [1 + j, -2j] ^T 1001000 2,3,4 [0,1,1,2] ^T [j, 1 + 2j] ^T 1001001 1,2,3 [2, -1, -1, 0] ^T [2-j, -1] ^T 1001010 1,2,3 [-2, -1, -1,0] ^T [-2-j, -1] ^T 1001011 2,3,4 [0, 2, -1, -1] ^T [-j, 2-j] ^T 1001100 2,3,4 [0, -2, -1, -1] ^T [-j, -2-j] ^T 1001101 1,3,4 [-1,0,2, -1] ^T [-1 + 2j, -j] ^T 1001110 1,3,4 [-1,0, -2, -1] ^T [-1-2j, -j] ^T 1001111 1,2,4 [-1, -1,0,2] ^T [-1, -1 + 2j] ^T 1010000 1,2,4 [-1, -1,0, -2] ^T [-1, -1-2j] ^T

The size of the transmit symbol vector set S ^BW is equal to the size of the set S of dimension-symbol combinations in the first embodiment. Therefore, the modulator 230 can map the symbols generated by the spatial lattice modulation method according to the first embodiment one-to-one with the transmission symbols of the Barnes Wall lattice structure to change the transmission symbol set. However, the modulator 230 can select and map some of the elements of S ^BW even if the sizes of the two sets are not the same. In the present specification, such a modulation method is referred to as a Barnes Wall Spatial Lattice Modulation with Barnes Wall (SLM-BW).

이므로

이지만, S ^BW 의 경우 평균 심볼 벡터의 에너지는

이고

이므로, S ^BW 가 S보다 큰

값을 가진다. 따라서 S ^BW 를 송신 신호로 사용하면 높은 신호 대 잡음비(SNR: Signal to Noise Ratio)에서 감쇠된 오류율을 나타낸다. For S , the energy of the mean symbol vector is

Because of

, But for S ^BW , the energy of the mean symbol vector is

ego

Therefore, when S ^BW is larger than S

Value. Therefore, when S ^BW is used as a transmission signal, it shows the attenuated error rate at a high signal-to-noise ratio (SNR).

4 is a graph illustrating a bit error rate of a spatial lattice modulation method and an existing spatial modulation method according to an embodiment of the present invention.

Referring to FIG. 4, in a system with four transmit antennas, four RF chains, four receive antennas (N _t = 4, N _RF = 4, N _r = 4) It can be seen that the modulation method exhibits a further reduced bit error rate. Also, it can be seen that the performance is improved when using the Barnes Wall spatial grid modulation method. The frequency efficiency also shows that additional performance can be obtained using the Barnes Wall spatial lattice modulation method.

In this embodiment, for example, mapping of a symbol mapped to a dimension-symbol combination to a symbol based on a barnes wall lattice structure has been described. However, this embodiment is applicable to a lattice structure other than the Barnes Wall lattice structure (for example, Structure) can be applied.

Third Example : Multiplexing and Modulation Method by Antenna Grouping of Spatial Grid Modulation

5 is a block diagram illustrating a transmitting apparatus according to another embodiment of the present invention.

으로 그룹핑될 수 있다. 이 경우, 송신 장치는 각 송신 안테나 그룹에 대하여 독립적인 비트열을 송신 심볼 벡터에 매핑할 수 있다. 예를 들어 4개의 송신 안테나를 포함하는 송신 장치는 2개의 송신 안테나를 포함하는 독립적인 2개의 송신 안테나 그룹으로 나뉘어 데이터를 송신할 수 있다. 2-PAM을 사용하는 경우, 각 송신 안테나 그룹은 각각 제1 실시예의 송신 심볼 집합 S 및 제2 실시예의 송신 심볼 집합 S ^BW 를 송신할 수 있다. 따라서 송신 장치는 log₂81+log₂81=12.64 비트를 전송할 수 있다. 이와 같은 송신 안테나 그룹화의 장점 중 하나는 각 안테나 그룹마다 다른 변조 계수를 사용하여 다양한 전송 속도를 만들어 낼 수 있다는 것이다.When fitted with a N _t transmit antennas in a transmitting apparatus, a plurality of N _t transmit antennas transmit antenna group

Lt; / RTI &gt; In this case, the transmitting apparatus can map an independent bit stream for each transmission antenna group to a transmission symbol vector. For example, a transmitting apparatus including four transmitting antennas can transmit data by being divided into two independent transmitting antenna groups including two transmitting antennas. When 2-PAM is used, each transmission antenna group can transmit the transmission symbol set S of the first embodiment and the transmission symbol set S ^BW of the second embodiment, respectively. Therefore, the transmitting device may transmit the _{log 2 81 + log 2 81 =} 12.64 bits. One of the advantages of such a transmission antenna grouping is that various modulation rates can be used for each antenna group to produce various transmission rates.

5, a transmitter includes a division unit 510, a first modulator 520, a second modulator 520, a first Tx antenna group 540, and a second Tx antenna group 550, .

The division unit 510 may divide the input data into independent bit strings according to the number of transmission antenna groups. 5, when _Nt transmission antennas are grouped into the first transmission antenna group 540 and the second transmission antenna group 550, the division unit 510 divides the input data into the first bit string and the second transmission antenna group 550, It can be divided into 2-bit columns.

The first modulator 520 may map the data (first bit string) input from the dividing unit 510 to the corresponding dimension-symbol combination based on the mapping information as shown in Table 1. Based on this, a transmission symbol set S can be generated. The transmission symbols generated by the first modulation unit 520 may be transmitted through the corresponding one of the transmission antennas included in the first transmission antenna group 540 based on the mapping information as shown in Table 1. [

The second modulator 530 maps the data (second bit string) input from the divider 510 to the dimension-symbol combination according to the second embodiment and outputs the generated transmission symbol set S to a predetermined symbol For example, a symbol based on a Barnes Wall lattice structure) to generate a transmit symbol set S ^BW . The transmission symbols generated by the second modulator 530 may be transmitted through the corresponding one of the transmission antennas included in the second transmission antenna group 550 based on the mapping information as shown in Table 1. [

6 is a flowchart showing a transmission method according to the first embodiment of the present invention.

The transmitting apparatus may map the input data to the dimension-symbol combination on the basis of the mapping information preset in the transmitting apparatus (S610). At least one modulation symbol may be generated based on the mapping (S620). The mapping information may be generated based on the number of antenna dimensions and the number of symbols used for modulating the data.

After that, the transmitting apparatus can transmit the modulation symbol generated based on the mapping information through the corresponding one of the plurality of transmission antennas (S630).

7 is a flowchart showing a transmission method according to a second embodiment of the present invention.

The transmitting apparatus may map input data based on the mapping information preset in the transmitting apparatus to a dimension-symbol combination, and may generate at least one modulation symbol based on the mapping (S710, S720). Thereafter, the transmitting apparatus may map the generated at least one modulation symbol to a predetermined symbol (S730). Here, the predetermined symbol may be a symbol derived based on the Barnes Wall generating matrix, for example. At this time, the transmitting apparatus can determine whether the number of symbols generated in step S720 is equal to the number of the predetermined symbols. If the number of symbols generated in step S720 is equal to the number of the predetermined symbols, the transmitting apparatus may map the symbols generated in step S720 one-to-one to the predetermined symbols. However, if the number of symbols generated in step S720 is not equal to the number of predetermined symbols, the transmitter may select some symbols among the predetermined symbols and map the symbols generated in step S720 to the selected symbols.

Thereafter, in step S740, the transmitting apparatus selects a transmission antenna corresponding to the modulation symbol mapped to the predetermined symbol among a plurality of transmission antennas based on the mapping information, and transmits the corresponding symbol through the selected transmission antenna.

8 is a flowchart showing a transmission method according to the third embodiment of the present invention.

The transmitting apparatus can group a plurality of transmitting antennas included in the transmitting apparatus into a first transmitting antenna group and a second transmitting antenna group (S810). The input data can be divided into independent bit strings according to the number of transmission antenna groups.

Thereafter, the transmitting apparatus maps each bit string to a dimension-symbol combination for a corresponding transmission antenna group based on preset mapping information (S820), and generates at least one modulation symbol based on the mapping S830). Then, the modulation symbol generated based on the mapping information can be transmitted through the corresponding transmission antenna in the corresponding Tx antenna group (S840). At this time, symbols according to the first embodiment can be transmitted through the first transmission antenna group, and symbols according to the second embodiment can be transmitted through the second transmission antenna group.

9 is a block diagram illustrating a receiving apparatus according to an embodiment of the present invention.

9, the receiving apparatus includes a plurality of receiving antennas 910 and 920, an interference removing unit 930, a channel estimating unit 940, a first demodulating unit 950, a second demodulating unit 960, An interleaving unit 970, and a decoding unit 980.

FIG. 9 shows a receiving apparatus capable of demodulating independent transmission symbol vectors when a bit string is transmitted to a plurality of groups according to the third embodiment, for example. Hereinafter, a case where data is transmitted in two independent groups having two transmission antennas when four transmission antennas are used will be described as an example.

The transmit vector x = [ x ₁ x ₂ x ₃ x ₄ ] ^T can be transmitted in two groups of vectors [ x ₁ x ₂ ] ^T and [ x ₃ x ₄ ] ^T. This can be expressed by the following equation (11).

In Equation (11), h _i denotes the i-th row of the wireless communication matrix H. To decode the first group [ x ₁ x ₂ ] ^T , the interference from the second group [ x ₃ x ₄ ] ^T must be removed.

Therefore, the interference canceller 930 receives a vector corresponding to a null space of the interference channel in the received signal from the first receiving antenna group 910 and the received signal from the second receiving antenna group 920, So that interference between signals can be eliminated. The interference cancellation matrix can be expressed by the following equation (12).

을 y 에 곱하게 되면 다음의 수학식 13과 같이 간섭이 제거되므로, [x ₁ x ₂ ]^T 을 [x ₃ x ₄ ]^T 로부터의 간섭이 제거된 상태로 복호할 수 있다. [x ₃ x ₄ ]^T 또한

을 y 에 곱하여 간섭이 제거된 상태로 복호할 수 있다.

Is multiplied by y , interference can be removed as shown in Equation (13), so that [ x ₁ x ₂ ] ^T can be decoded with the interference from [ x ₃ x ₄ ] ^T removed. [ x ₃ x ₄ ] ^T

Can be multiplied by y to decode the interference-free state.

의 복호 복잡도를

로 감소시킬 수 있다. 상기의 예제에서는 간섭 제거부(930)가 두 개의 심볼벡터를 ZF(Zero Forcing) 기반으로 검출하는 방식을 설명했지만, 노이즈 효과를 고려한 MMSE(Minimum Mean Square Error) 기법 그리고 두 개의 심볼벡터를 순차적으로 검출하는 SIC(Successive Interference Cancellation)기법 또한 사용할 수 있다.Therefore, the interference canceller 930 eliminates inter-coral interference by the above-

Decoding complexity of

. In the above example, the interference canceller 930 detects two symbol vectors based on ZF (Zero Forcing). However, the minimum mean square error (MMSE) technique considering the noise effect and the two symbol vectors are sequentially Successive Interference Cancellation (SIC) techniques can also be used.

The channel estimation unit 960 can estimate the channel of the MIMO wireless communication system using the pilot transmitted from the transmission apparatus.

The first demodulating unit 950 and the second demodulating unit 960 receive the signals from the first receiving antenna group 910 based on the mapping information defined on the basis of the number of the antenna dimensions and the number of symbols used for signal modulation, And demodulate the received signal and the signal received at the second receive antenna group 920. [ The mapping information may be preset in the receiving apparatus. Or radio resource control (RRC) signaling from the transmitting apparatus.

The deinterleaving unit 970 can deinterleave the demodulated signals in the first demodulating unit 950 and the second demodulating unit 960.

The decoding unit 980 can decode the deinterleaved signal and restore the original data.

10 is a flowchart illustrating a receiving method according to an embodiment of the present invention.

Referring to FIG. 10, a receiving apparatus according to an embodiment of the present invention can receive a signal from a transmitting apparatus including a plurality of transmitting antennas using at least one receiving antenna (S1010). Thereafter, the receiving apparatus can remove inter-signal interference by multiplying the received signal by a vector corresponding to the null space of the interference channel (S1020). The received signal may be decoded based on mapping information defined on the basis of the number of virtual antenna dimensions and the number of symbols used for modulating the signal (S1030). Here, the mapping information may be preset in the receiving apparatus, or may be received in advance from the transmitting apparatus through RRC signaling or the like.

11 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 11, a transmitting apparatus 1100 includes a processor 1110, a memory 1120, and an RF antenna (radio frequency) antenna 1130. The memory 1120 is coupled to the processor 1110 and stores various information for driving the processor 1110. [

The processor 1110 implements all of the operations, functions, procedures, and / or methods of the transmitting device 1100 published herein. For example, the processor 1110 maps input data to a dimension-symbol combination based on mapping information preset in the transmitting apparatus 1100 according to the first embodiment described above, and based on the mapping, Symbol, and may transmit the at least one modulation symbol through at least one of the plurality of transmit antennas. The mapping information may be generated based on the number of antennas and the number of symbols used for modulating data. The processor 1110 maps the generated at least one modulation symbol to a predetermined symbol according to the second embodiment and transmits a modulation symbol mapped to the predetermined symbol among a plurality of antennas based on the mapping You can choose an antenna. If the number of the generated at least one modulation symbol is equal to the number of the predetermined symbols, the processor 1100 may map the generated at least one modulation symbol one-to-one to the preset symbol. If the number of the generated at least one modulation symbol is smaller than the number of the predetermined symbols, the processor 1100 selects a part of the predetermined symbols and outputs the generated at least one modulation symbol to the selected symbol Can be mapped. In addition, the processor 1100 groups the plurality of transmit antennas into a first transmit antenna group and a second transmit antenna group according to the above-described third embodiment, groups the first bit string of data into a dimension- Symbol combination and map the second bit stream of data to the dimension-symbol combination for the second transmit antenna group. The processor 1110 may include an application-specific integrated circuit (ASIC), other chipset, logic circuitry, and / or a data processing device.

Memory 1120 can include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage media, and / or other storage devices.

The RF antenna 1130 includes a plurality of transmitting and receiving antennas and is connected to the processor 1110 to transmit signals of the transmitting apparatus 1100 and receive signals of the receiving apparatus 1200. [ The RF antenna 1130 may include a baseband circuit for processing radio signals.

When embodiments of the present disclosure are implemented in software, embodiments of the present disclosure may be implemented with modules (processes, functions, and so on) that perform the functions. The module may be stored in memory 1120 and executed by processor 1110. [ The memory 1120 can be internal or external to the processor 1110 and can be coupled to the processor 1110 in a variety of well known ways.

The receiving device 1200 includes a memory 1210, a processor 1220, and an RF antenna 1230.

The memory 1210 is coupled to the processor 1220 to store various information for driving the processor 1220. The RF antenna 1230 includes a plurality of transmitting and receiving antennas and is connected to the processor 1220 to transmit signals of the receiving apparatus and / or receive signals of the transmitting apparatus.

The processor 1220 may implement all of the operations, functions, processes, and / or methods of the receiving apparatus 1200, in particular those that implement the functions, processes and / or methods suggested herein. For example, the processor 1220 may decode the received signal based on mapping information defined based on the number of antenna dimensions and the number of symbols used for modulating the signal. The processor 1220 may receive the mapping information from the transmitting apparatus 1100 via the RF antenna 1230 before receiving the data signal. The processor 1220 may also remove inter-signal interference by multiplying the received signal by a vector corresponding to the null space of the interference channel when the transmitter transmits a signal according to the third embodiment. Processor 1220 may include an ASIC, another chipset, logic circuitry and / or a data processing device. Memory 1210 may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices.

Claims (20)

1. A transmitting apparatus in a wireless communication system supporting multiple input multiple output (MIMO)
A plurality of transmit antennas; And
Mapping input data to a combination of a plurality of virtual antenna dimensions and at least one modulation symbol (hereinafter referred to as a dimension-symbol combination), generating at least one modulation symbol based on the mapping, A processor for transmitting the at least one modulation symbol via at least one processor,
Lt; / RTI &gt;
Wherein the virtual antenna dimension comprises:
Wherein the antenna is defined as an antenna that transmits an equivalent real signal among the complex signals transmitted by the transmission antenna. The method according to claim 1,
The processor comprising:
And maps bits of the data to the dimension-symbol combination on the basis of mapping information preset in the transmitting apparatus. 3. The method of claim 2,
The mapping information includes:
And the number of symbols used for modulation of the data is generated based on the number of virtual antenna dimensions and the number of symbols used for modulation of the data. 3. The method of claim 2,
The processor comprising:
Mapping the generated at least one modulation symbol to a predetermined symbol and selecting an antenna for transmitting a modulation symbol mapped to the predetermined symbol among the plurality of antennas based on the mapping information. 5. The method of claim 4,
The processor comprising:
Mapping the generated at least one modulation symbol to the predetermined symbol in a one-to-one mapping when the number of the at least one modulation symbol is equal to the number of the predetermined symbols, and if the number of the at least one modulation symbol And selects at least one of the predetermined symbols and maps the generated at least one modulation symbol to the selected symbol. 5. The method of claim 4,
The pre-
Wherein the symbol is a symbol selected in order of low powers among symbols corresponding to a predetermined grid generation matrix. The method according to claim 1,
The processor comprising:
Grouping the plurality of transmit antennas into a first transmit antenna group and a second transmit antenna group, mapping a first bit stream of the data to a dimension-symbol combination for the first transmit antenna group, And maps a column to a dimension-symbol combination for the second transmit antenna group. A transmitting method of a transmitting apparatus in a wireless communication system supporting multiple input multiple output (MIMO)
Mapping incoming data to a combination of a plurality of virtual antenna dimensions and at least one modulation symbol (hereinafter referred to as a dimension-symbol combination);
Generating at least one modulation symbol based on the mapping; And
Transmitting the at least one modulation symbol through at least one of the plurality of transmit antennas
Lt; / RTI &gt;
Wherein the virtual antenna dimension comprises:
Wherein the antenna is defined as an antenna that transmits an equivalent real signal among the complex signals transmitted by the transmission antenna. 9. The method of claim 8,
Wherein the mapping step comprises:
And mapping bits of the data to the dimension-symbol combination based on mapping information preset in the transmitting device. 10. The method of claim 9,
The mapping information includes:
The number of virtual antenna dimensions, and the number of symbols used for modulation of the data. 10. The method of claim 9,
After the generating step,
Mapping the generated at least one modulation symbol to a predetermined symbol; And
Selecting an antenna for transmitting a modulation symbol mapped to the predetermined symbol among the plurality of antennas based on the mapping information
Further comprising the step of: 12. The method of claim 11,
Wherein mapping the generated at least one modulation symbol to a predetermined symbol comprises:
Mapping the generated at least one modulation symbol to the predetermined symbol in a one-to-one mapping when the number of the at least one modulation symbol is equal to the number of the predetermined symbols, and if the number of the at least one modulation symbol Selecting at least one of the predetermined symbols when the number of symbols is less than a predetermined number of symbols, and mapping the generated at least one modulation symbol to the selected symbol. 12. The method of claim 11,
The pre-
Wherein the symbol is a symbol selected in order of low powers among symbols corresponding to a predetermined grid generation matrix. 9. The method of claim 8,
Prior to the mapping step,
Further comprising grouping the plurality of transmit antennas into a first transmit antenna group and a second transmit antenna group,
Wherein the mapping step comprises:
Mapping the first bit string of the data to a dimension-symbol combination for the first transmission antenna group and mapping a second bit string of the data to a dimension-symbol combination for the second transmission antenna group . 1. A receiving apparatus in a wireless communication system supporting multiple input multiple output (MIMO)
At least one receiving antenna for receiving signals from a transmitting apparatus including a plurality of transmitting antennas; And
A processor for decoding the signal based on mapping information defined based on the number of virtual antenna dimensions and the number of symbols used for modulating the signal,
Lt; / RTI &gt;
Wherein the virtual antenna dimension comprises:
And is defined as an antenna that transmits an equivalent real signal among the complex signals transmitted by the transmitting apparatus. 16. The method of claim 15,
The processor comprising:
And receives the mapping information from the transmitting apparatus before receiving the signal. 16. The method of claim 15,
The processor comprising:
Wherein the signal is multiplied by a vector corresponding to a null space of an interference channel to remove inter-signal interference. A receiving method of a receiving apparatus in a wireless communication system supporting multiple input multiple output (MIMO)
Receiving a signal from a transmitting apparatus including a plurality of transmitting antennas using at least one receiving antenna; And
Decoding the signal based on mapping information defined based on the number of virtual antenna dimensions and the number of symbols used for modulating the signal
Lt; / RTI &gt;
Wherein the virtual antenna dimension comprises:
Wherein the antenna is defined as an antenna that transmits an equivalent real signal among the complex signals transmitted by the transmitting apparatus. 19. The method of claim 18,
Before the receiving step,
Further comprising receiving the mapping information from the transmitting device. 19. The method of claim 18,
Wherein the decoding comprises:
And removing the inter-signal interference by multiplying the signal by a vector corresponding to a null space of the interference channel.

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